1. Field of the Invention
The present invention relates to the preparation of extended or delayed release sweeteners, and more particularly to the preparation of sweeteners in an encapsulated form suitable for incorporation in to food products which must be chewed such as chewing gums and chewable confections. The encapsulated sweeteners result in extended or prolonged release of sweetness in the food products and can also provide improved shelf stability for sweeteners such as L-aspartyl-L-phenylalanine and similar sweeteners which can be stabilized by an acidic environment.
2. Description of the Prior Act
Much effort has been directed to extending release of sweeteners and stabilizing sweeteners in food products and particularly in chewing gum compositions. Activity in this area has focused on dipeptide sweeteners such as L-aspartyl-L-phenylalanine methylester (aspartame). Aspartame has been widely recognized as an extremely good-tasting non-caloric sweetener for use in a variety of food products among which are chewing gum products. Unfortunately, aspartame is extremely unstable in the presence of moisture and undergoes hydrolytic degradation and subsequent loss of sweetness. Elevated temperatures and specific pH ranges may accelerate the hydrolytic degradation. Additionally, aspartame is known to react with a number of flavorings and chemicals such as aldehydes and ketones. For example, aspartame loses its sweetness due to chemical reactions in the presence of flavor aldehyde-containing oils such as cinnamon. These flavor oils are used in food products and are popular in chewing gum and other confectionery products. These compositions also generally contain moisture and may be exposed to elevated temperatures during their shelf-life. The result is the loss of aspartame and the corresponding loss of sweetness contributed thereby in the gum or food product.
Numerous attempts have been made to stabilize and extend sweetness release of aspartame and other sweeteners in chewing gums as well as other food products. U.S. Pat. No. 4,384,004 to T. Cea et al., discloses solid particles of aspartame encapsulated by a coating material selected from the group consisting of cellulose, cellulose derivatives, arabinogalactin, gum arabic, polyolefines, waxes, vinyl polymers, gelatin, zein and mixtures thereof, wherein the amount of said coating material to aspartame is from 1:1 to 1:10. More particularly, the coating materials include cellulose, methyl cellulose, ethyl cellulose, cellulose nitrate, cellulose acetate phthalate, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, arabinogalactan; polyethylene, polymethacrylates, polyamides, ethylenevinyl acetate copolymers, polyvinylpyrrolidone; gum arabic; paraffin wax, carnauba wax, spermaceti, beeswax; stearic acid, stearyl alcohol, glyceryl stearate; gelatin, zein and mixtures thereof.
The method of coating employed in this reference involves suspending the aspartame particles in a stream of air that passes through a zone of atomized liquid droplets of the coating material, so that the coating material is deposited on the surface of the aspartame. More than one coating may be used whereby the inner coating is water-soluble and the outer coating is water-insoluble.
U.S. Pat. Nos. 4,122,195 and 4,139,939, both to Bahoshy et al., fix aspartame by preparing it with a material such as gum arabic or the reaction product of a compound containing a polyvalent metallic ion, with an ungelatinized starch acid-ester of a substituted dicarboxylic acid, by a spray drying technique, where the aspartame and a film former are prepared in an emulsion.
U.S. Pat. No. 4,374,858, to Glass et al., discloses an aspartame sweetened chewing gum having improved sweetness stability wherein the chewing gum piece has aspartame coated on its surface, as opposed to incorporating it in the chewing gum mix.
EPA No. 81110320.0 published June 16, 1982 (Publication No. 0053844), to Ajinomoto Co., Inc. discloses a stabilized dipeptide-based sweetening composition comprising (a) from 20 to 60% by weight of solid fat, (b) from 10 to 30% by weight emulsifier, (c) from 10 to 30% by weight polysaccharide and (d) not more than 30% by weight of dipeptide sweetener. The compositions are prepared by heating the mixture of the ingredients, cooling, and pulverizing to obtain powder or granules of the composition to obtain a ASTM mesh size of smaller than 12. Spray drying the mixture is also disclosed.
U.S. Pat. No. 4,105,801 to Degliotti, discloses a confectionery comprising a core portion and shell adheringly enveloping the core portion, whereby the shell is formed by an intimate mixture of microcrystals of xylitol with a solid fatty substance to each 100 parts by weight of xylitol. The fatty substance is preferably a mono-, di- or triglyceride having a melting range of between 20.degree. and 60.degree. C.
U.S. Pat. No. 3,389,000 to Toyonaka et al., disclosed protective coatings for granular nucleoside-5-phosphates, the coatings being edible fats melting between 40.degree.-100.degree. C. and derived from plants and animals. Hydrogenated oils such as soybean oil, cottonseed oil, almond oil, castor oil, linseed oil, mustard oil, olive oil, grapefruit seed oil, palm oil, palm kernel oil, rapeseed oil, rice bran oil and the like and mixtures thereof. This reference discloses a process of preparing the granular product from a liquid mixture of fats and nucleoside-5-phosphates which are sprayed from a pressure nozzle and the resultant granules cooled and recovered.
U.S. Pat. No. 4,382,924, to Berling, discloses liquid oral dosage forms for vitamins or pharmaceutical materials comprising an edible oil, high potency lipid soluble sweetener such as saccharin and lipid soluble flavorant. The edible oil may be a polyol fatty acid ester having at least four fatty acid ester groups and each fatty acid having from about 8 to about 22 carbon atoms. The oil, sweetener and flavor oil are mixed and heated and then cooled to provide a palatable liquid dosage form.
For general discussion of spraying a fatty material onto sweeteners and the like see U.S. Pat. Nos. 3,949,094 and 3,976,794 both to Johnson, and U.S. Pat. No. 3,867,556 to Darragh. U.S. Pat. No. 4,293,572 to Silva et al., disclosed the application of a dispersion of an emulsified fat with a solution of dextrin, saccharin or a polysaccharide to a food product as a barrier against moisture. U.S. Pat. No. 3,527,647 discloses a process of agglomerating particles to cause them to collide and form agglomerates.
U.S. Pat. No. 4,597,970 to Sharma, et al., discloses a chewing gum composition comprising a gum base and agglomerated sweetener delivery system capable of effecting a controlled release of core material comprising:
(A) at least one natural or artificial core material selected from the group consisting of amino acid based sweeteners, dipeptide sweeteners, glycyrrhizin, saccharin and its salts, acesulfame salts, cyclamates, steviosides, talin, dihydrochalcone compounds, flavoring agents and mixtures thereof; and PA0 (B) a hydrophobic matrix consisting essentially of
(i) lecithin; and PA1 (ii) an edible material having a melting point in the range of about 25.degree. C. to about 100.degree. C. selected from the group consisting of (a) fatty acids having an iodine value of about 1 to about 10, (b) natural waxes, (c) synthetic waxes and (d) mixtures thereof; and PA1 (iii) at least one glyceride.
PCT publication No. WO 84/0320 published Aug. 30, 1984 discloses a food-grade shellac encapsulant for active chewing gum ingredients. Encapsulation of sweetener, flavoring agent, food grade acid and pharmaceutical agents to achieve a gradual and controlled release of such ingredients is presented. The amount of shellac to sweetener such as aspartame is about 1:20 to about 0.9:1.
It is therefore desirable to develop a method for preparing sweeteners in a manner which extends sweetness of chewed edible products such as chewing gums and also increases the shelf stability of the dipeptide sweeteners such as aspartame when incorporated into these edible products.